Without limiting the scope of the invention, its background is described in connection with ionically masked pharmaceutical agents that are rapidly disintegrating and delivered in an extended or sustained-release form, as an example.
Methods for sustained release are known in the art. One such method of making sustained release particles is taught in U.S. Pat. No. 6,120,787, issued to Gustafsson, et al., which teach a method for preparing parenterally administrable sustained release microparticles. The method includes preparing core particles in an aqueous medium that is essentially free from organic solvent and the biologically active substance is entrapped therein during or after preparation, e.g., drying the core particles. The coating may be the same release-controlling polymer, which is added by an air suspension technique to create a shell on the core particles without any detrimental exposure of the active substance to organic solvent.
Another sustained-release composition includes an amorphous polymer as taught in U.S. Pat. No. 6,613,358, issued to Randolph, et al., which provides for a sustained release composition of a pharmaceutical substance that includes: a biocompatible polymer that is highly amorphous and a pharmaceutical substance in a hydrophobic ion complex with an amphiphilic material. A compressed antisolverit method for manufacturing the composition it also taught, as are various product forms incorporating the composition and various uses for the composition.
Yet another sustained release drug formulation is taught in U.S. Pat. No. 5,980,945, issued to Ruiz in which a sustained release drug formulation includes a drug; a biodegradable polymer that is insoluble in water; and an oil vehicle in which both the drug and the polymer are dissolved. The oil vehicle may contain 10-100% by volume of a pharmaceutically acceptable oil and 0-90% by volume of a pharmaceutically acceptable liquid carrier for the drug or the polymer.
Finally, U.S. Pat. No. 5,674,533 issued to Santus, et al., teaches pharmaceutical compositions for the controlled release of the anti-tussive, moguisteine, in a liquid suspension designed either as ready-to-use and time-stable liquid formulations with a shelf-life of at least two years, or as dry formulations that are reconstituted with water when needed and then remain stable throughout the treatment period. Santus teaches the use of coated microgranules for the controlled release of moguisteine having sizes ranging from 50 to 500 μm, preferably from 90 to 300 μm, which are capable of remaining easily in suspension in a liquid for extended times. The microgranules have a moguisteine core, with one or more optional plasticizers and excipients, granulated into microgranules having sizes smaller than 500 uniform surfaces, substantially spherical shapes, apparent densities of about 500 to 600 g/l and very low friabilities, which are made by wet-kneading micronised moguisteine using water or a mixture of water and other solvents. These initial microgranules have controlled-release properties by, a first coating having essentially hydrophilic characteristics, which isolates the microgranules; followed by a second coating having lipophilic characteristics on top of the first coating; and a third coating having hydrophilic characteristics.
Orally administered drug formulations may be provided to the patient in many dosage forms, including solid forms (e.g., capsules, caplets, effervescent or tablets) and liquid forms (e.g., solutions, syrups, emulsions or suspensions). Generally, orally administered drug formulations administered in solid dosage form are intended to be swallowed whole and any disagreeable taste can be easily masked with an exterior coating. However, some formulations are designed for rapid absorption of the active ingredient through the oral mucosa, e.g., chewing of the tablets, effervescent, and the like and thus result in tastes that are more difficult to mask. A growing market for these and other products is the pediatric and geriatric patients.
Many pharmaceutical compositions must be formulated as liquids for use by pediatric, geriatric patients, disabled persons, incapacitated patients and persons with dysphagia often have trouble swallowing. To alleviate this challenge a number of drug delivery protocols have been developed including rapid in-mouth disintegrating tablets, tablets which disintegrate in liquid prior to ingestion, liquids and syrups, gums and transdermal compositions. Unfortunately, these delivery methods can pose their own problems.
For example, immediate release compositions with rapid absorption of the active ingredient through the oral mucosa (e.g., rapid in-mouth disintegrating tablets, tablets that disintegrate in liquid prior to ingestion, liquids and syrups, gums) may have an unpleasant texture or even an unpalatable taste associated with the immediate release agent or other component of the composition.